Shrouded contact



United States Patent 3,140,141 HROUDED CONTACT Joseph A. Nava, Villa Park, Ill., assignor to The Pyle- JNational Company, Chicago, 111., a corporation of N ew ersey Filed May 10, 1962, Ser. No. 194,753 4 Claims. (Cl. 339256) This invention relates generally to electrical connectors and more particularly relates to an improved shrouded contact construction of the closed entry type wherein an elliptical spring engages the mating pin contact, thereby developing a current continuing function with a high degree of predictability and with low insertion and withdrawal forces.

In a socket-type contact as used in an electrical connector, it is required that the contact adequately carry a rated load with a minimum of insertion and extraction force. For example, if each contact in a multiple pin connector requires a separating force or engagement force, the total cumulative force in such a connector is likely to be so great that special handling tools are necessitated. In many environmental operating conditions, the time cycle allowed to engage and disengage the connectors must be at a minimum. Accordingly, the use of handling tools is undesirable.

In accordance with the principles of the present invention, a socket contact is provided which is characterized by the utilization of an elliptical spring resiliently engaging a mating pin, thereby carrying rated current as required with highly predictable results and with low insertion and withdrawal forces. The specific arrangement contemplated in the present disclosure has improved means for retaining the elliptical spring in association with the contact whereby the spring is kept from falling into the interior of the contact and wherein the spring is kept from twisting sideways.

It is an object of the present invention, therefore, to provide an improved shrouded contact construction.

Another object of the present invention is to provide an improved shrouded contact wherein the elliptical spring is kept from displacement or from falling into the interior of the contact.

Yet another object of the present invention is to provide an improved shrouded contact wherein the elliptical spring is kept from twisting sideways.

Many other objects and additional advantages of the present invention will become manifest to those versed in the art upon making reference to the detailed description which follows and the accompanying sheets of drawings in which a preferred structural embodiment of a contact embodying the principles of the present invention is shown by way of illustrative example.

On the drawings:

FIGURE 1 is a side elevational view of an improved contact provided in accordance with the principles of the present invention with the front socket portion broken away in part to show components of the invention in greater detail;

FIGURE 2 is an enlarged cross-sectional view taken one line 11-11 of FIGURE 1;

FIGURE 3 is an enlarged fragmentary cross-sectional view to illustrate additional details of construction of the fastening means between the sleeve and the connector;

FIGURE 4 is a side elevational view of an elliptical spring provided in accordance with the principles of the present invention;

FIGURE 5 is a top plan view of the spring of FIG- URE 4;

FIGURE 6 is a cross-sectional view showing the socket portion of the female connector of the present invention;

3,140,141 Fatented July 7, 1964 FIGURE 7 is a top plan View of the socket portion shown in FIGURE 6;

FIGURE 8 is a side elevational view of an alternative form of elliptical spring;

FIGURE 9 is a top plan view of the elliptical spring of FIGURE 8;

FIGURE 10 is an end view of the spring of FIGURES 8 and 9;

FIGURE 11 is a cross-sectional view of a socket portion of an alternative form of contact specifically adapted to accommodate the elliptical spring of FIGURES 8, 9 and 10; and

FIGURE 12 is a top plan view of the socket portion of FIGURE 11.

As shown on the drawings:

As shown on FIGURE 1, the socket contact of the present invention is indicated generally at It and may comprise any usual socket contact blank characterized as being of the closed entry type, that is, no axially separated socket fingers are provided. Rather, there is formed a generally cylindrical or tubular socket portion shown at 11 including an inner bore 12 forming the female part of an electrical connector.

- In the socket contact 10 illustrated herein by way of example, the actual socket portion 11 is separated from an additional body portion 13 by an annular groove or recess 14 which, in accordance with the principles of the present invention, develops a special retaining function. The body portion 13 may be stepped or recessed as at 16, 17, 18 and 19 to accommodate assembled relationship with related connector components, however, any suitable structural form of connector could be utilized insofar as the applicability of the principles of the present invention are concerned, and it should be understood that the form of the socket contact is not intended to specifically limit the scope of the present invention.

The socket contact is also provided with a rear barrel portion 20 which has formed therein a recess 21 intended to receive insertion of a bared conductor wire. To facilitate checking or inspection of the proper insertion of a wire conductor into the rear barrel portion 20, an inspection hole 22 is provided.

In accordance with the principles of the present invention, the socket portion 11 has an end wall 23 in which is formed a belled opening 24 by means of which a male pin 26 may be inserted into the bore 12 of the socket portion 11.

In order to apply pressure against the male pin 26, an elliptical spring shown generally at 27 is provided. The socket portion 11 has a slot 28 formed therein and the slot may be conveniently formed by means of a milling operation thereby providing ramp portions 29 and 30 at opposite ends of the slot 28 which is disposed longitudinally relative to the socket portion 11 and which is located inwardly of the end wall 23.

The elliptical spring 27 has a central bowed portion- 31 which is of such a width as shown at 32 as to be received in the slot 28 and supported on the ramp portions 29 and 30. Thus, the centrally bowed portion 31 extends into the bore 12 and resiliently engages the peripheral surface of the male pin 26.

The width of the slot 28 is preferably in such a proportion to the diameter of the male pin 26 as to provide resistance to probe damage. In other words, the male pin 26 cannot penetrate far enough into the slot 28 to damage the elliptical spring 27.

It is contemplated by the present invention to provide specific means for preventing the elliptical spring 27 from falling into the slot 28. In this regard, it will be noted the spring 27 is particularly characterized by the formation of ears 33, 33 at opposite ends of the bowed body portion 31. In the form of the elliptical spring 3 shown in FIGURES 4 and 5, the cars 33 comprise transversely extending fiat lugs of generally rectangular configuration, the lugs 33 extending transversely to provide a lengthwise component 34 of greater dimension than the width of the body portion 32 and a width component 36.

In the form of the invention illustrated in FIGURES 1-7, the socket portion 11 is provided with clearance for the cars 33 by a cross milling operation. Thus, a recess 37 is formed at each end of the slot 28 which constitutes a flat transversely extending recess intersecting each respective end of the slot 28 adjacent the ramp 29 and the ramp 30. The width of the recesses 37, 37 is controlled relative to the width dimension 36 of the ears or lugs 33 so that the spring 27 is kept from twisting sideways.

The spring 27 is held in the socket portion 11 of the contact by a sleeve which is fitted over the socket portion 11 of the contact and which covers the spring 27. It will be noted that the inner end of the sleeve 40 is moved into register with the peripheral groove 14. In this regard, the stepped body portion 13 provides an effective shoulder 41 against which the inner end of the sleeve 40, shown at 42, may engage whereupon the inner end of the sleeve is offset radially inwardly into the groove 14, thereby placing the sleeve 40 in firm assembly with the contact 10. The sleeve 40 not only retains the elliptical spring 27, but adds strength to the contact and encloses such openings as are provided in the female contact with the exception of the end opening 24 required for the entry of the male contact 26.

The form of the invention illustrated in FIGURES 8-12 is of comparable structural and functional characteristics but varies in the manner in which the spring is prevented from falling into the slot and is kept from twisting sideways. Accordingly, like reference numerals with the suffix a are used to designate like parts wherever possible.

In FIGURE 8 is shown an elliptical spring 27a having a bowed center body portion 31a. In this form of the invention, ears 33a are formed on the opposite ends of the elliptical spring 27a by a coining operation, thereby reducing the thickness of the ears as shown at to approximately one-half of the normal spring thickness. By the coining operation, the ears are extended transversely to a length dimension 34a and have a width dimension as indicated at 36a. Further, as shown in FIGURE 10, the ears 33a are curved to a radius shown at 51. Thus, to accommodate the ears 33a, the socket portion 11a is characterized by the formation therein of two circumferentially extending peripheral grooves 37a which may be formed by a directional milling operation on the contact body and the grooves 37a are formed to intersect the ends of the slot 28a adjacent the ramp portions 29a and 3011. Thus, the spring 27a is inserted into the slot 28a and is prevented from falling into the slot 28a by the ears 33a. The spring 27a is prevented from twisting sideways by the ears 33a by controlling the width of the grooves 370 in relation to the width of the ears 33a.

The spring 27a is again held in the body of the contact by a sleeve 40 fitted over the socket portion of the contact and covering the spring. The sleeve is retained by crimping into the groove formed in the socket portion 11.

The provision of the elliptical spring with the special retaining means and anti-twisting feature accomplishes the objectives of the present invention and provides an improved closed entry connector which displays great resistance to probe damage. The contact construction minimizes cutting of rubber insulation upon insertion of the contacts into insulation and provides an arrangement wherein the spring is protected against external damage. Further, the insertion and extraction forces can be easily varied by changing the spring thickness. The finished construction provides a particularly clean appearance with a smooth exterior and permits an arrangement wherein complete plating coverage may be effected because the components are assembled after plating is effected.

Although minor modifications might be suggested by those versed in the art, it should be understoood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.

I claim as my invention:

1. A connector comprising a female contact,

a front socket portion on said contact having an axial end opening,

for receiving a male pin, and means for applying pressure to the male pin comprising an elliptical spring disposed longitudinally and having a bowed portion extending into the interior of the socket portion to engage the male p said contact having a longitudinal slot formed in the wall of the socket portion to receive said spring, a retainer sleeve on said socket portion covering said spring,

and ears on the ends of said spring to keep the spring from falling into the slot,

said contact having a relief recess formed at each end of the slot to form a corresponding ear, said relief recess comprising a fiat transverse recess intersecting each respective end of the slot, and said car being sized with respect to the width of said recess to prevent twisting of the spring sideways. 2. A connector comprising a female contact, a front socket portion on said contact having an axial end opening,

for receiving a male pin, and means for applying pressure to the male pin comprising an elliptical spring disposed longitudinally and having a bowed portion extending into the interior of the socket portion to engage the male p said contact having a longitudinal slot formed in the wall of the socket portion to receive said spring, a retainer sleeve on said socket portion covering said spring,

and ears on the ends of said spring to keep the spring from falling into the slot,

said contact having a relief recess formed in each end of the slot to receive a corresponding ear,

said relief recess comprising a circumferentially extending peripheral groove at each end of the slot and each said ear having a width relative to the width of the groove to prevent twisting of the spring sideways.

3. A connector as defined in claim 2, each said ear comprising an integral part of said spring of less thickness than the body of the spring and displaced transversely on a radius of curvature conforming to the shape of the groove.

4. A generally cylindrical hollow contact having an axial opening in one end for receiving a male pin,

said contact having an axially extending slot formed in the walls thereof,

means for applying spring pressure against the male pin comprising an elliptical spring inserted in said slot,

means for preventing said spring from falling into said slot comprising an ear wider than said spring formed one each end of said spring,

said contact having a relief area formed therein axially outwardly of each end of said slot to seat a corresponding ear,

and a sleeve fitted over the slotted portion of said contact and covering said spring and clamping said ears against said contact,

said relief area comprising a flat transverse recess in- 5 tersecting the end of said slot and said ear comprising a transversely extending lug received in said recess.

References Cited in the file of this patent 5 UNITED STATES PATENTS 1,642,696 Rateike Sept. 20, 1927 1,704,422 Belunes Mar. 5, 1929 2,716,744 Swanson et a1. Aug. 30, 1955 3,009,130 Redslpb et a1 Nov. 14, 1961 10 Great Britain Jan. 11, 1961 

2. A CONNECTOR COMPRISING A FEMALE CONTACT, A FRONT SOCKET PORTION ON SAID CONTACT HAVING AN AXIAL END OPENING, FOR RECEIVING A MALE PIN, AND MEANS FOR APPLYING PRESSURE TO THE MALE PIN COMPRISING AN ELLIPTICAL SPRING DISPOSED LONGITUDINALLY AND HAVING A BOWED PORTION EXTENDING INTO THE INTERIOR OF THE SOCKET PORTION TO ENGAGE THE MALE PIN, SAID CONTACT HAVING A LONGITUDINAL SLOT FORMED IN THE WALL OF THE SOCKET PORTION TO RECEIVE SAID SPRING, A RETAINER SLEEVE ON SAID SOCKET PORTION COVERING SAID SPRING, AND EARS ON THE ENDS OF SAID SPRING TO KEEP THE SPRING FROM FALLING INTO THE SLOT, SAID CONTACT HAVING A RELIEF RECESS FORMED IN EACH END OF THE SLOT TO RECEIVE A CORRESPONDING EAR, SAID RELIEF RECESS COMPRISING A CIRCUMFERENTIALLY EXTENDING PERIPHERAL GROOVE AT EACH END OF THE SLOT AND EACH SAID EAR HAVING A WIDTH RELATIVE TO THE WIDTH OF THE GROOVE TO PREVENT TWISTING OF THE SPRING SIDEWAYS. 